Answer:
E = 0.4 kWh
Explanation:
Given that,
The power of a bulb, P = 40 W
Time, t = 10 hours
We need to find the energy used by the bulb. Let it is equal to E. So,
[tex]E=P\times t\\\\E=40\times 10\\\\E=400\ W-h\\\\or\\\\E=0.4\ kWh[/tex]
So, 0.4 kWh of energy would be needed.